“We know that these mice have a mutation in a gene on chromosome 3,” said Emma. “The gene is scientifically close enough toto the region in which one of our CdLS individuals has a chromosone break to warrant investigation.”

The ‘linkage’ study – looking at the DNA characteristics of CdLS people and their relatives who don’t have the syndrome has yet to yield any conclusive data.

However, two additional families – one from the UK and the other from Poland – are now available to supply DNA to the US-based project and this should boost the chances of identifying trends.

The research into chromosomal abnormalities suggests that possibly more than one gene may be involved in CdLS.